Consumer devices like personal computers or smartphones play an important role in the life of most hearing impaired users. However, with few exceptions, manufacturers design these devices for normal hearing users. Consequently, the audio output of these devices is often inadequate for hearing impaired users.
In these devices loud signals are treated in the same way as soft signals, while hearing impaired users need more gain for soft signals than for loud signals. Thus, hearing impaired users are left with the options to buy louder speakers or simply to crank up the volume. FIG. 1 shows a personal computer used by a hearing impaired user that does not have hearing aids.
Some devices offer predefined equalizers that change the gain as function of the audio frequency. However, this is insufficient for hearing impaired users because the equalizer is not adapted to their individual hearing loss.
Users that own and use hearing aids, receive individual amplification while they use consumer devices, as illustrated in FIG. 2. This solution is also far from optimal, because the audio signal transmitted by the consumer device needs to be picked up by the microphone of the hearing aid and during this transformation the signal suffers from the limited sound quality of the microphone and the limited frequency range of the hearing aid. Also, the hearing aid microphone picks up additional environmental noise and the hearing aid is not aware of the type of input signal (for example speech or music) and it is not able to optimize its signal processing to the type of signal.
In both scenarios sketched above (with and without hearing aids) the computational power of consumer devices is not used to help the hearing impaired user to better understand speech or to enjoy music.
Although the majority of consumer products are not made with hearing impaired users in mind, a small number of products do exploit the computational power of consumer devices to provide hearing loss compensation for hearing impaired users. One example concerns iPhone applications for the hard of hearing, some of them including music players tailored for allowing hearing impaired users to enjoy music, e.g., http://listenapp.jacoti.com. As another example, Bluetooth headsets from the company Sound ID provide personalized sound processing that can be beneficial both for hearing impaired users and for normal users in difficult hearing situations.
Also some patents relate to the adaptation of consumer devices for hearing impaired users. U.S. Pat. No. 7,257,372 relates to a Bluetooth enabled hearing aid, where the hearing aid includes an acoustic echo canceller. Patent documents U.S. Pat. Nos. 6,944,474 and 7,529,545 propose a mobile phone including resources applying measures of an individual's hearing profile, a personal choice profile and induced hearing loss profile (which takes into account the environmental noise), separately or in combination, to build the basis of sound enhancement.
In application US2005/135644 a digital cell phone is described with built-in hearing aid functionality. The device comprises a digital signal processor and a hearing loss compensation module for processing digital data in accordance with a hearing loss compensation algorithm. The hearing loss compensation module can be implemented as a program executed by a microprocessor. The proposed solution also exploits the superior performance in terms of processing speed and memory of the digital cell phone as compared to a hearing aid. The wireless download capabilities of digital cell phones are said to provide flexibility to the control and implementation of hearing aid functions. The incoming digitized signal is processed by a digital filter bank, whereby the received signals are split into different frequency bands. Each filter in the filter bank possesses an adequate amount of stop-band attenuation. Additionally, each filter exhibits a small time delay so that it does not interfere too much with normal speech perception (dispersion) and production. In the proposed system the audio signal captured during a phone call is used as the main input. Hence, the proposed solution is limited to providing hearing loss compensation during phone calls.
Existing solutions can be represented by a scheme as in FIG. 3. It corresponds to a schematic representation of existing solutions in consumer devices tailored for hearing impaired users. A computer executes an application that implements hearing loss compensation and uses standard or specialized speakers. While sound produced by the application with hearing loss compensation can provide excellent speech intelligibility and music quality, the audio output of all the other applications executed on the same consumer device are not adapted to the needs of the hearing impaired user.
For hearing impaired users it would be desirable to see manufacturers of operating systems (OS) for computers (e.g., Windows, Linux, Mac OS X) and smartphones (e.g., Android, Windows Phone, iOS, Bada) to support hearing impaired users of their system. Such a support does not exist at present, but it would allow the processing of all sound output according to the amplification need of the individual user. There is clearly a need for such a solution.